When you click on this option, a dialog appears having controls
marked Reference Baseline, OK, and Cancel. A single .CAL or
.FRD file can hold data for only one channel, which is shown
below 'Channel:' at the top of the dialog. This is also the
channel shown on the Y axis, which you can change by
toggling off unwanted channel display buttons.

A horizontal cursor also appears on the trace, passing through
the average of all the spectrum values between the normal
solid and dotted cursors. The Reference Baseline control
defaults to this value.

You may adjust the solid and dotted cursors to define the
region you want to become the baseline for the .CAL file.
Alternatively, you can manually enter a baseline value
and the horizontal cursor will move to match. (You can't
drag the horizontal cursor vertically, however.)

The specific baseline value is not critical for subsequent Y-log
spectrum work using the .CAL file, since when it is loaded
into a User Line the complete response curve will be in
effect. However, in waveform or linear spectrum modes there
is no frequency-dependent calibration correction, so the
baseline serves to define an approximate overall sensitivity
in those modes.

If the response has obvious dips and peaks, it may be best to
locate the baseline on the flattest portion of the spectrum,
or perhaps on the flattest portion of the midrange or other
particular region of interest.

When you are satisfied with the baseline, hit OK to go to
a normal Windows file Save As dialog. The saved file will
have a .CAL extension by default. To instead save in .FRD
format, scroll the 'Files of type' to that selection.
Otherwise, hit Cancel or the Escape key to abandon the save at
any time.

A standard Daqarta .CAL or enhanced .FRD file will be
created from the data. The 'Unit:' field will hold the name of
whatever units were in effect when the file was created,
defaulting to 'Volt' unless some other name was set in the
User Line dialog and User Units was active. The baseline
value will become the 'Sens:' reference value, and that value
will be subtracted from all the spectrum dB values.

Once you have saved the .CAL or .FRD file, you may load it in
the appropriate User Line dialog as a
Mic or Spkr .CAL file. It may also be used instead of
a .CRV file for Spectrum Curves.

You should create the .CAL or .FRD file at the same sample rate
that you will use it. If you use it at a lower rate than
recorded, Daqarta will interpolate and the results may still
be fairly good. If you use the file at a higher rate than
recorded, Daqarta will attempt to linearly extrapolate the
upper values from the highest two recorded values, with
typically poor results.

Macro Notes:

The SaveCAL macro will only work when there is a Y-log
spectrum on the screen. Also, it has no effect if any File
Open or Save As dialog is already active.

SaveCAL= without a name will open the reference baseline
dialog. After you hit OK there, the Save As dialog will open
with no default file name.

SaveCAL="MyFile" will open the reference baseline as above,
but when you hit OK the Save As dialog will have the default
name set to MyFile. (Note that quotes are needed around
all filenames in macros.) If you accept this by hitting
Enter or the Save button in that dialog, Daqarta
will assume you want to save a file named MyFile.CAL, or
MyFile.FRD or MyFile.CRV or MyFile.LIM if you
select one of those file types. If the file already exists,
you will be prompted to replace it.

A.SaveCAL="MyFile" will save MyFile.CAL as soon as
you click OK to set the baseline, without any Save As dialog.
Note that if the file already exists, it will be
overwritten without any confirmation prompt.

A.SaveCAL="MyFile.FRD" will save MyFile.FRD as above,
without an overwrite prompt. Similarly,
A.SaveCAL="MyFile.CRV" will save MyFile.CRV and,
A.SaveCAL="MyFile.LIM" will save MyFile.LIM without
a prompt.

SaveCAL can use string variables and expressions.
For example, SaveCAL=Field1 will use the contents of
Field1 as the default file name, and A.SaveCAL=Field1
will save a file with that name directly.

Similarly, if the Macro Variable Var0 holds a value of 12,
then SaveCAL="Test"+Var0 will set a default file name of
Test012.

To save a file without opening the dialog or having to enter a
reference value manually, you can set the reference ahead of
time via CalSaveRef=-10 (or whatever dB value you
choose). Then, for example, A.SaveCAL="MyFile.CRV" will
save a Mirror Curve file automatically with no dialog or
prompt.